Which form of Kepler's third law can you use to relate the period T and radius r of a planet in our solar system as long as the unit year is used for the period and astronomical unit is used for the radius? (= means proportional to in this case)

Question

O T ^ 2 = r
O T = r ^ 2;
O T ^ 2 = r ^ 3;
O T ^ 3 = r ^ 2

Answer 1

The correct form of Kepler's third law that relates the period T and radius r of a planet in our solar system when using years for the period and astronomical units for the radius is:

O T ^ 2 = r ^ 3